Biologically Guided Orthodontics: Addressing Maxillary Transverse Deficiency in Adults

Before and after the palatal expansion using a conventional expander

Introduction

A 26-year-old patient presented with persistent jaw pain, mandibular retrusion, and concerns about her facial esthetics following prior orthodontic treatment. Her primary complaints included chronic jaw discomfort, airway-related sleep disturbances, bruxism, and difficulty achieving restful sleep. Dr. Daisy Song applied a biologically guided orthodontic approach to address these functional and esthetic concerns while prioritizing airway and facial harmony.

Assessment & Diagnosis

Clinical evaluation revealed a Class II dental relationship, mild anterior open bite, overjet, posterior tongue posture, and maxillary transverse constriction. CBCT imaging confirmed a narrow maxilla, restricted nasal cavity, and compromised oral–pharyngeal spatial relationships. Cephalometric analysis highlighted a vertical growth pattern, increased lower facial height, occlusal plane cant, and mandibular rotational patterns. TMJ assessment demonstrated a limited range of motion and muscular tension.

Treatment Objectives

The main goals were to:

• Expand the maxillary arch to create sufficient tongue space.

• Improve occlusal relationships and maintain labiolingual inclinations within biologically acceptable limits.

• Reduce lower facial height and correct occlusal plane cant.

• Enhance mandibular posture, TMJ comfort, and facial esthetics.

• Support long-term stability and airway function.

Treatment Plan & Methodology

Dr. Song employed a slow, biologically guided maxillary expansion with a conventional Hyrax expander, chosen for patient comfort and gradual adaptation. Treatment included:

• Fixed orthodontic appliances for alignment.

• Temporary anchorage devices (TADs) to selectively intrude maxillary teeth and reduce lower facial height.

• Interim occlusal splints to support TMJ function.

• Minimal inter-arch elastics to avoid vertical strain.

• Transition to clear aligners for finishing and detailing.

• Guidance on physiological tongue posture, and referral for adjunctive procedures as needed (lingual frenectomy, third molar extraction).

Results & Outcomes

• The patient achieved improved occlusal alignment and facial balance.

• Maxillary expansion created adequate tongue space, supporting airway function.

• TMJ discomfort and muscle tension were reduced.

• Overall esthetics and functional outcomes were optimized while maintaining biologic safety and periodontal health.

Conclusion

This case demonstrates the value of a biologically guided, airway-conscious orthodontic approach for adult patients. By integrating skeletal, dental, and soft tissue considerations, clinicians can achieve functional improvements, esthetic harmony, and patient satisfaction without compromising long-term stability.

Facial changes with expansion and orthodontic treatment